One more thing to add to the Elastic reliability:

> We recommend installing the Java 8 update 20 or later, or Java 7 update 55 or later. Previous versions of Java 7 are known to have bugs that can cause index corruption and data loss. Elasticsearch will refuse to start if a known-bad version of Java is used.

http://www.elastic.co/guide/en/elasticsearch/reference/1.5/s...